1. Field of the Invention
This invention relates to a treating liquid to be used after finishing chemical mechanical polishing (CMP) and to a method of manufacturing a semiconductor device using the treating liquid.
2. Description of the Related Art
In recent years, a trend to further promote the fineness of wirings has been rapidly advanced concomitant with a trend to further promote the integration of an LSI. Additionally, it is now considered imperative to adopt new materials for alleviating the delay of wiring RC. Under the circumstances, it is now being attempted to employ low resistant Cu (ρ: 1.8 μΩ-cm) as a conductive material and to employ an insulating film of low dielectric constant (k: <2.5) as an insulating material.
The Cu wiring is mainly formed as damascene wiring by CMP. The insulating film and wiring that have been formed by CMP are inevitably accompanied with residues such as dusts (abrasive particles and shavings) and unreacted slurry. As the washing liquid to removing these residues, there have been conventionally employed those containing a chelate complexing agent and a surfactant. However, since intervals between wirings is required to be as small as 0.1 μm or less in a semiconductor device of the next generation, a trace amount of fine residues that has been considered to raise no problems up to date may cause wiring failures such as short-circuit between wirings or the deterioration in withstanding voltage of insulating film as the space between wirings is further narrowed in future.
Additionally, since most of the insulating film of low dielectric constant contains an organic component, the surface of the film is hydrophobic and hence hardly wettable to water. Therefore, dusts easily adsorb on the surface of insulating film during the CMP treatment or the washing treatment. Moreover, the dusts once adsorbed in this manner can be hardly removed, thus giving rise to failures to form wirings which are normally electrically isolated from each other. Further, the insulating film having a low dielectric constant is also accompanied with a problem that it can be easily scratched.
As the washing liquid to be employed for removing minute particles and metal impurities which are adhered to the surface of substrate, there has been conventionally proposed a treating liquid containing aliphatic polycarboxylic acid and a reducing agent. Further, there has been also proposed a treating liquid containing resin particles for performing a post-CMP treatment. There are increasingly demands that the surface of the insulating film in which a conductive material is buried, in particular, the surface of the insulating film of low dielectric constant that has been subjected to the CMP treatment is further enhanced in cleanness and also that the surface washed is enabled to advance to the next step in a stabilized state. Especially, when the semiconductor substrate is allowed to dry subsequent to the post-CMP treatment and then left to stand in an environment of clean room, the surface of conductive material is abnormally oxidized, thus raising the problem of short-circuiting of wirings.